Made of galvanized steel and come with plastic bottoms. Each compartment is 12 inches wide for larger breeds. Easy partial bolt together and pop rivet construction. You will require a pop rivet gun for assembly. Click for Rivet Gun Lid, front, back and perches are made of plastic to help reduce harbouring places for mites and lice. Side panels and perch brackets are galvanized. This unit is 48 inches wide.